on this site anything refered to as cider is 'real cider' which is produced by pressing apples then allowing the naturally present yeasts to ferment the juices over a period of time.
Cider can be made from any vareity and combination of apples, I can't say I know enough to have a favourite but I do generally prefer ciders that come from the East of England to those better known and fashionable West Country ciders. I've been told that the difference is down to the variety of apples used, West Country ciders tend to be made from cider-apples, which are something like a cross between crab-apples and normal apples. In the East the apples used for cider tend to be either actual cooking or eating apples and as such are a better quality. I find East Country ciders are smoother and less sickly.
One thing I have learned about cider is to never smell it - real cider usually smells like a sewer.